Network Scheduling :
Precedence Diagram Method
• In AOA and precedence diagramming, the
activities are represented by nodes rather
than arrows.
PDM Logical Relationship
• The left side of the PDM node is designed the “start
side” and the right side is designed the “finished
side”.
• Because of the importance of the side, PDM uses
arrowheads to identify the direction of relationship.
• Precedence diagramming allows more flexibility in
modeling relationship than AOA diagramming. AOA
diagramming allow only one kind of logical
relationship : a preceding activity must be complete
before any succeeding activity can begin.
• The four logical relationship used by PDM are : Finish
to start, Start to start, Finish to finish, Start to finish
FS Relationship
• The most common precedence diagramming
relationship.
• The succeeding activity cannot start until he
preceding activity has been completed.
• FS relationship can be expressed in three forms if lag
is used, zero lag, positive and negative lag.
SS Relationship